Question: We are given a table for the city of Detroit, Michigan USA for the period of 1961 to 1973 with the following information: a column with the number of full-time police per 100,000 citizens and a column with the number of homicides per 100,000 citizens.
Year | Police | Homicides |
|---|---|---|
1961 | 260.35 | 8.6 |
1962 | 269.8 | 8.9 |
1963 | 272.04 | 8.52 |
1964 | 272.96 | 8.89 |
1965 | 272.51 | 13.07 |
1966 | 261.34 | 14.57 |
1967 | 268.89 | 21.36 |
1968 | 295.99 | 28.03 |
1969 | 319.87 | 31.49 |
1970 | 341.43 | 37.39 |
1971 | 356.59 | 46.26 |
1972 | 376.69 | 47.24 |
1973 | 390.19 | 52.33 |
- On the same x-axis representing the year, construct the time series of the number of police and the number of homicides on the same graph.
- Identify the variable that demonstrated the higher percentage increase relative to its initial value (police or homicides), and share your conclusions on the matter.
- Did the increase in police officers have an impact on the murder rate? Why?
Answer
Year | Police | Homicides |
|---|---|---|
1961 | 260.35 | 8.6 |
1962 | 269.8 | 8.9 |
1963 | 272.04 | 8.52 |
1964 | 272.96 | 8.89 |
1965 | 272.51 | 13.07 |
1966 | 261.34 | 14.57 |
1967 | 268.89 | 21.36 |
1968 | 295.99 | 28.03 |
1969 | 319.87 | 31.49 |
1970 | 341.43 | 37.39 |
1971 | 356.59 | 46.26 |
1972 | 376.69 | 47.24 |
1973 | 390.19 | 52.33 |
Time series of the number of police and the number of homicides on the same graph
The variable that demonstrated the higher percentage increase relative to its initial value from 1961 to 1973 can be calculated using the formula below:
(Fina value-Initial value)/(Initial value)×100%
The percentage change for Police = (390.19-260.35)/260.35×100%=49.87%
The percentage change for homicides = (52.33-8.6)/8.6×100%=508.49%
Thus, homicides exhibited the swiftest increase during this period.
From the graph, increase in police officers have a negative impact on the murder rate, it can be seen that from 1961 to 1973, the more the police, the more the murder rate.
I cannot pinpoint the exact cause of the surge in homicides solely from the provided data. Numerous factors, including economic conditions, societal unrest, or alterations in law enforcement tactics, may have contributed to this escalation.